I agree with Iceman, but that's me, too. A Saito .56 head sticking out from under would look good, and the muffler would still fit under the cowl, and you canuse a DuBro extension to route it back toward center. What I do on all my planes for the needle adjuster is take a short 2-56 hex head screw, grind the threads down just a little, and it will fit the hole in the end of the adjuster. Snug the set screw down and you can use a long ball-tip hex wrench to adjust your carb. I make a guide tube from brass (about 1/8 inch diameter) and glue it to a space that puts it at the proper distance from the firewall and aligns it with the screw in the adjuster and a small hole in the side of the cowl. All you see in the cowl is a 1/8 inch hole, hardly noticeable. See attached pics of two setups.

I'm currently building BUSA's Bristol M-1, your Eindecker would make a great dog-fighting partner.